Advances in semiconductor processing and logic design have permitted an increase in the amount of logic that may be present on integrated circuit devices. As a result, computer system configurations have evolved from a single or multiple integrated circuits in a system to multiple hardware threads, multiple cores, multiple devices, and/or complete systems on individual integrated circuits. Additionally, as the density of integrated circuits has grown, the power requirements for computing systems (from embedded systems to servers) have also escalated. Furthermore, software inefficiencies, and its requirements of hardware, have also caused an increase in computing device energy consumption. In fact, some studies indicate that computing devices consume a sizeable percentage of the entire electricity supply for a country, such as the United States of America. As a result, there is a vital need for energy efficiency and conservation associated with integrated circuits. These needs will increase as servers, desktop computers, notebooks, Ultrabooks™, tablets, mobile phones, processors, embedded systems, etc. become even more prevalent (from inclusion in the typical computer, automobiles, and televisions to biotechnology).
In some software applications, individual processor performance variability across nodes of a compute cluster can result in software failures. At the same time, the nature of modern processors is to take advantage of environmental capacity such as power or thermal constraints and increase processor clock frequency until one or more of these limits are reached. With die-to-die silicon variation, processor operation is generally non-deterministic. The solution for many users who seek to normalize performance across nodes is to disable altogether opportunistic turbo mode operation in which clock frequencies of a processor are increased. While this can more readily ensure determinism of operation across the nodes, a significant amount of performance is lost.